This invention relates to self-lubricating wear-resistant composite materials.
There are known two types of self-lubricating composite materials. Composite materials obtained by blending a solid lubricant with a metal powder matrix, molding the blend and sintering the molding belong to one of the types, and composite materials produced by impregnating a sintered porous metal matrix with a solid lubricant belong to the other type. Generally, those of the latter type are superior to those of the former type in terms of wear rate and mechanical properties. Composite materials of the latter type are, however, difficult to manufacture, if the impregnation of a solid lubricant such as, for example, molybdenum disulfide or graphite, which do not melt during the preparation process, is wanted in the composite. Composite materials of the former type are, in contrast, easy to produce because the solid lubricant and the metal both are blended in a powdery form.
In the aforementioned process of manufacturing self-lubricating composite materials, there arise cases in which certain metals behave so as to react chemically with particular kinds of solid lubricants. In such a case, the composite material to be obtained consequently has enhanced mechanical strength and reduced electrical conductivity but exhibits poor lubricating property unless the particular kind of solid lubricant is used in large amounts greater than is stoichiometrically consumed in the reaction with the metal. When the composite material is produced by using a solid lubricant which in the process of production is inactive with the metal matrix, it exhibits an excellent lubricating property but has ion mechanical strength because the binding force of metal matrix is not sufficient.
It is an object of this invention to provide self-lubricating wear-resistant composite materials which excel in lubricating property, wear rate as well as in mechanical strength.